The field of the invention is integrated circuit substrate manufacturing and printed circuit board manufacturing.
During the processing of dielectric materials used in substrates, it is often necessary to precisely position various components/features of the material. As an example, if one drills a through hole in a base layer and later etches traces onto the surfaces of the base layer which are to be connected via the through hole, the through hole/via and traces must be precisely positioned relative to each other.
Similarly, pads on one layer of a multi-layer device being fabricated will often need to line up/achieve registration with a pad or other component on a corresponding layer when the layers are laminated together. Proper registration requires precisely locating the positions of various components on each layer and the layers relative to each other.
Precise positioning of components is complicated by the fact that the dimensions of dielectric materials such as polyimide films change as temperature and humidity change. The dimensional changes make it difficult to achieve proper registration between layers and to properly position components relative to each other. The difficulty increases as the number of components on each layer increases and the size of such components decreases. Thus, there is a continuing need for new methods and apparatus which allow proper registration between layers despite the affect of temperature and humidity on the dimensions of the layers.
The present invention is directed to allowing a work piece to achieve equilibrium with a controlled environment, particularly in regard to temperature and humidity/water content, prior to precision operations so as to minimize any problems resulting from dimensional changes. The present invention is particularly applicable to the creation of multi-layer devices such as interconnects used in IC packaging and very dense printed circuit boards.
Various objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention, along with the accompanying drawings in which like numerals represent like components.